Mercurial > hg
view mercurial/sshserver.py @ 26375:3686fa2b8eee
windows: insert file positioning call between reads and writes
fopen() and fdopen() have a unique-to-Windows requirement that
transitions between read and write operations in files opened
in modes r+, w+, and a+ perform a file positioning call
(fsetpos, fseek, or rewind) in between. While the MSDN docs don't
say what will happen if this is not done, observations reveal
that Python raises an IOError with errno 0. Furthermore, I
/think/ this behavior isn't deterministic. But I can reproduce
it reliably with subsequent patches applied that open revlogs
in a+ mode and perform both reads and writes.
This patch introduces a proxy class for file handles opened
in r+, w+, and a+ mode on Windows. The class intercepts calls
and audits whether a file positioning function has been called
between read and write operations. If not, a dummy, no-op seek
to the current file position is performed. This appears to be
sufficient to "trick" Windows into allowing transitions between
read and writes without raising errors.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Sun, 27 Sep 2015 18:46:53 -0700 |
parents | 72b36785d7f4 |
children | 56b2bcea2529 |
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# sshserver.py - ssh protocol server support for mercurial # # Copyright 2005-2007 Matt Mackall <mpm@selenic.com> # Copyright 2006 Vadim Gelfer <vadim.gelfer@gmail.com> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from __future__ import absolute_import import os import sys from . import ( hook, util, wireproto, ) class sshserver(wireproto.abstractserverproto): def __init__(self, ui, repo): self.ui = ui self.repo = repo self.lock = None self.fin = ui.fin self.fout = ui.fout hook.redirect(True) ui.fout = repo.ui.fout = ui.ferr # Prevent insertion/deletion of CRs util.setbinary(self.fin) util.setbinary(self.fout) def getargs(self, args): data = {} keys = args.split() for n in xrange(len(keys)): argline = self.fin.readline()[:-1] arg, l = argline.split() if arg not in keys: raise util.Abort("unexpected parameter %r" % arg) if arg == '*': star = {} for k in xrange(int(l)): argline = self.fin.readline()[:-1] arg, l = argline.split() val = self.fin.read(int(l)) star[arg] = val data['*'] = star else: val = self.fin.read(int(l)) data[arg] = val return [data[k] for k in keys] def getarg(self, name): return self.getargs(name)[0] def getfile(self, fpout): self.sendresponse('') count = int(self.fin.readline()) while count: fpout.write(self.fin.read(count)) count = int(self.fin.readline()) def redirect(self): pass def groupchunks(self, changegroup): while True: d = changegroup.read(4096) if not d: break yield d def sendresponse(self, v): self.fout.write("%d\n" % len(v)) self.fout.write(v) self.fout.flush() def sendstream(self, source): write = self.fout.write for chunk in source.gen: write(chunk) self.fout.flush() def sendpushresponse(self, rsp): self.sendresponse('') self.sendresponse(str(rsp.res)) def sendpusherror(self, rsp): self.sendresponse(rsp.res) def sendooberror(self, rsp): self.ui.ferr.write('%s\n-\n' % rsp.message) self.ui.ferr.flush() self.fout.write('\n') self.fout.flush() def serve_forever(self): try: while self.serve_one(): pass finally: if self.lock is not None: self.lock.release() sys.exit(0) handlers = { str: sendresponse, wireproto.streamres: sendstream, wireproto.pushres: sendpushresponse, wireproto.pusherr: sendpusherror, wireproto.ooberror: sendooberror, } def serve_one(self): cmd = self.fin.readline()[:-1] if cmd and cmd in wireproto.commands: rsp = wireproto.dispatch(self.repo, self, cmd) self.handlers[rsp.__class__](self, rsp) elif cmd: impl = getattr(self, 'do_' + cmd, None) if impl: r = impl() if r is not None: self.sendresponse(r) else: self.sendresponse("") return cmd != '' def _client(self): client = os.environ.get('SSH_CLIENT', '').split(' ', 1)[0] return 'remote:ssh:' + client